The invention relates to a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine.
German Laid-Open Application DE 10 2006 012 242 A1 has disclosed a fuel injection valve for an internal combustion engine, which has a valve body, in which there is formed a pressure space which can be filled with fuel at high pressure and from which at least one injection opening starts. Arranged in the pressure space is a longitudinally movable valve needle, which interacts by means of a sealing surface with a conical valve seat formed in the pressure space in order to open and close the at least one injection opening. To ensure that sufficient fuel flows between the sealing surface of the valve needle and the valve seat to the injection openings to achieve an appropriate injection rate, the valve needle must traverse a certain minimum stroke. This is because it is first necessary to cross the region in which the gap between the sealing surface and the valve seat exerts a restricting effect and the injection pressure prevailing at the injection openings is reduced. With a large minimum stroke for achieving the full injection pressure, however, it is not possible to achieve a rapid succession of injections. In the laid-open application mentioned above, therefore, a conically formed valve seat with an opening angle of between 75° and 100° is proposed. Compared with fuel injection valves which have a conical valve seat with a conventional opening angle of about 60°, the fuel injection valve proposed has the advantage that the stroke of the valve needle required to traverse the seat restriction region is smaller and, as a result, a rapid succession of injections at a high injection pressure is possible. Moreover, the larger opening angle of the valve seat is supposed to reduce flow-induced disturbing forces on the valve needle, which can cause axial misalignment of the valve needle.
Given the constant increase in injection pressures, strength considerations, especially in the region of the valve seat, are nowadays to the fore in the development of modern fuel injection valves. In this context, the seat geometry chosen has a major influence on the operation of the fuel injector.
It is therefore the object of the present invention to provide a fuel injector which has a high strength, especially in the region of the valve seat.